1. In the US, you can get a 25 pound bag of rice for $11, 25 pound bag of flour for $7, etc.
Rice should be viewed as a food extender that when added to something like a can of tomato soup will dramatically increase the caloric value of the food and allow many to be filled with it.
2. I have worked time and again with Mylar bags. I have tried them in all kinds of different thicknesses, sizes, manufactures, suppliers, and so forth.
I have tried sealing them in multiple ways as well and I have found that they have an unacceptably high failure rate.
Typically, Mylar bags are sent through the mail folded up (especially the larger sizes) and the corners of the folds ends up creating microscopic holes that leak air.
My success rate with Mylar bags has been between 5% and 40% depending on all sorts of variables.
In my hands, these bags are just too expensive with too great a failure rate (with failures often times taking a year or so to manifest itself) to be used.
3. Vacuum food sealers offer a great and economical method for storing food. Vacuum food bags are heavy duty and have a failure rate in my hands of less than 5% when care is taken.
(Do not use the pleated vacuum bags because they are a nightmare to get to work well with an unacceptably high failure rate. It seems the pleating creates mall channels that are hard to seal properly which leads to failure.)
Also, you can get add ons that allow you to vacuum seal foods in jars.
4. A great many foods do not need to be stored under a vacuum or in an inert atmosphere to remain viable for extended periods. The real issue that destroys foods are moisture and heat.
If you can store your food at or below room temperature while keeping the moisture levels relatively low, then things like rice, pasta, beans, and so forth, can be stored without problem for decades.
5. You can get prepackaged (under a vacuum) dry milk, flour, dried apples, oats, beans, rice, sugar, and so forth via mail order or from stores of the Mormon Church at one of their stores across the country (https://providentliving.lds.org/self-reliance/food-storage/home-storage-center-locations?lang=eng). The dry milk is exceptional and well packaged.
6. The greatest threat to food storage is vermin. A mouse or rat can go through a Mylar bag in an instant and they will given any opportunity.
I store most of my food such as sugar, pasta, flour, rice, beans, and such, in plastic trash cans with a locking lid. (You can enhance or ensure the seal using duct tape.)
These keep the mice and such out and when stored in their original packages in a cool dry environment, the food is good for decades. A month or so ago we sacrificed some pasta that we put into storage in a plastic trash can 14 years ago.
It was in its original packaging with no Mylar bag, no oxygen absorbers, no water getters, or anything else, and no one in the family could taste anything different when we cooked it up and ate it.
Additionally, as a research chemist who has taught Toxicology as well as Biochemistry at the university for nearly 20 years, I know that these products are nutritionally fine and have not lost any nutritional value.
7. Learn how to can.
When done properly, food will last indefinitely. When we cooked up the pasts form 14 years ago, we also used canned tomato sauce that was canned a bit over 10 years ago and it was excellent.
The bottom line is that one experiment is worth a thousand hypotheses. People need to take the information they can get and then try with trial and error to see what works for them and what does not.
Blindly taking advice and using it without some experimentation or long term monitoring is a classic method of failure. Hope this helps.
If you have anything to add, feel free to leave your ideas or thoughts in the comment box below…